Continental Motors is making a voluntary recall at its own expense of 9,600 cylinder heads used on Continental 520-, 550-, and O-470 series engines. The recall was made when inspections of aircraft with 400 or more hours were found to have cracks on top and at the spark plug locations.

All the engines affected are six-cylinder engines. Continental will pay for parts and labor and replace the cylinders over the next year. Special service numbers have been established to answer customers’ questions. On Friday, Feb. 13, phone lines will be open from 7 a.m. to 7 p.m. CST at 888/200-7565 and 251/436-8665. Hours this weekend are 8 a.m. to 4:30 p.m. Information is also available online.

It will cost Continental $18 million to replace the 9,600 suspect cylinders. The problem was traced to a single casting machine at a subcontractor location that created cylinder walls that were too thin. The subcontractor was not named, and a Continental spokesman had no comment on whether his firm will attempt to recoup the cost of replacement from the subcontractor. The casting machine has been destroyed.

The problem was discovered by Continental in the last few days. Immediate coordination with the FAA resulted in Thursday’s announcement of the problem. To date, only 36 cylinders have been found to have cracks. The cylinders have an EQ3 designation and were made since November 2007.